As a conventional technique of this type, there is, for example, the technique disclosed in JP-A-11024744. According to this conventional technique, a construction machine is provided with sensors for detecting operation states, an operation data collecting device for collecting operation data detected by the sensor, and a communication device and antenna for transmitting the operation data collected in the operation data collecting device. The communication device includes a communication unit. Also disclosed are a base station for receiving signals, which have been outputted from the communication device, via a communication satellite, for example, and user equipment connected to the base station via a communication line. The base station is arranged at a place remote from the construction machine, and the user equipment is such that can directly receive the operation data of the construction machine via the antenna arranged on the construction machine.
According to this conventional technique, the operation data collected by the operation data collecting device are transmitting in their entirety to the base station or the user equipment. By the base station or the user equipment, the operation data of the construction machine are controlled and can be retrieved by a user as needed.
With the above-described conventional technique, various operation data of the construction machine which is performing work can be obtained by the base station at the remote place or by the user equipment. These operation data can be used, for example, for predicting a maintenance schedule for the construction machine, predicting a replacement schedule to a new construction machine, and providing the customer of the construction machine with information on the construction machine.
When the construction machine is a hydraulic excavator or the like, for example, the operation data include an extremely wide variety of data, that is, data based on operating pilot pressures such as digging time, traveling time and swinging time, data based on a main hydraulic circuit such as pump load, swing load and travel load, data relating to an engine such as operation time, coolant temperature and fuel level, data associated with working oil such as working oil temperature and existence or non-existence of filter clogging, position data indicating an actual position of the construction machine, and data on the use of a special attachment, such as a breaker or crusher, mounted upon performing special work.
The conventional technique is high in communication cost, because it transmits the above-mentioned various data in their entirety, for example, to the base station via a communication satellite or to the user equipment by using a telephone line. When transmission is performed via the communication satellite, for example, the communication cost is the product of the size of data and a unit price per byte. When the telephone line is used, on the other hand, the communication cost is the product of time of transmission, which is determined depending upon the size of data, and a unit price per unit time. Accordingly, the communication cost increases with the size of data to be transmitted.
For the user, on the other hand, such various data as mentioned above are not often required in their entirety. Further, necessary operation data may differ depending upon the user.
The present invention has been completed in view of the above-mentioned current circumstance of the conventional technique, and has as an object thereof the provision of an information transmitting system for a construction machine, said information transmitting system being capable of supplying operation data of the construction machine as much as needed by its user or the like without unnecessary data.